1. Field of the Invention
The present invention relates to electric machines and electric drive systems having a power source that provides power to an electric motor through an electric motor controller. In particular, the present invention relates to discharging a capacitor coupled between the power source and the electric motor controller.
2. Background Art
For the purposes of the present invention, electric machines and electric drive systems relate to systems which use an electric motor to drive a load. These systems can include a number of components, and typically, such systems include at least a power source, an electric motor controller, and an electric motor. In this arrangement, the electric motor controller can receive power from the power source, which the electric motor controller then controllably transfers to the electric motor for driving a load.
For DC power sources, a capacitor can be coupled between the power source and the electric motor controller to smooth the DC power output from the power source. The coupling of the capacitor to the power source causes the capacitor to become charged. The capacitor remains charged until its stored energy can be dissipated.
In the foregoing system, there exists a need to discharge this stored capacitive energy when the DC power source is disconnected. In addition, there exists a need to provide a cost effective approach to discharging the stored capacitor energy.